As telephony continues to merge with computers with "telecommunications" now supporting both voice and data communications, new challenges and opportunities are presented. For example, telephone subscribers in the past simply used their telephone line for voice communication from a telephone. Today, a telephone subscriber often uses his telephone line for both voice and data communications. As a result, there is a good chance that an incoming call intended for that subscriber will find the line busy either with a traditional voice telephony communication or with a data communication. Data communications may be particularly problematic because a subscriber may connect himself to an external communications network, such as the Internet, for an extended time period as anyone who has become addicted to Internet "surfing" will attest One problem then is how to contact such a subscriber when he is surfing on the Internet.
In a pure telephony environment, if a subscriber is engaged in extended telephone conversations, he can anticipate problems others will have in reaching him by subscribing to a call waiting service. Consequently, when the subscriber is talking on the telephone, the presence of an incoming call is indicated in some detectable fashion to the subscriber. The subscriber may then momentarily interrupt his current conversation to take the incoming call to determine the identity of the incoming caller and decide which call to take. Another solution is to subscribe to a call completion service which continuously tries to complete a call between the two parties when the telephone line of the called party is busy.
But these two solutions are limited. For example, call completion services typically time out if the called party is busy more than thirty minutes. After thirty minutes on the Internet, some surfers are just warming up. A problem with call waiting is that it is not well adapted to data communications. It is not a problem to interrupt a typical voice communication briefly with an incoming second call, aside from some mild distraction to the earlier caller. This is not the case with data communications. A call waiting signal during a data communication would completely disrupt the data session being conducted over the subscriber's telephone line.
Accordingly, the problem is one of how to establish communication with a party who is engaged, for example, on an extended data communication without having to resort to traditional call waiting or call completion options and their respective shortcomings. Call forwarding is a possible solution. Call forwarding is a known technique where a subscriber who will be away from his telephone or does not want to be interrupted redirects calls to another telephone. However, conventional call forwarding is an inflexible service. Once a subscriber specifies a forwarding number to which the subscriber's calls are to be forwarded, all of the subscriber's call are forwarded to that number. If the subscriber wants to take some calls and forward others, he must remember to manually activate and deactivate the call forwarding service at the appropriate times. Manual activation and deactivation is inconvenient and subject to subscriber memory/discipline. Moreover, call waiting and/or call completion services may conflict with call forwarding.
What is needed is a selective call forwarding approach that specifically permits a subscriber to selectively but still automatically is forward telephone calls to another number when the subscriber is engaged in specific, selected communications. For example, it would be desirable to permit a user to selectively divert incoming calls to an alternative number only when the subscriber is engaged in a data communication. Typically, data communications are limited to specific telephone numbers such as an Internet access number and/or a particular telephone number that the subscriber commonly employs for data communications. What is needed is a service that permits a user to identify one or more outgoing telephone numbers, which when engaged by the subscriber, automatically cause incoming calls to the subscriber to be forwarded to a prescribed forwarding number such as the subscriber's mobile telephone number. This selective call forwarding would prevent disruption of the data communication and still permit the subscriber to be reached by incoming callers. Such call forwarding should take place automatically so that the subscriber does not have to manually forward his calls each time he desires calls to be forwarded, e.g., each time he decides to take an Internet session.
The problems noted above are addressed and resolved by employing selective call forwarding method and system in accordance with the present invention. In response to a request from a subscriber for the selective call forwarding service, a selective call forwarding service record is created for the subscriber which includes the subscriber's telephone number, a "trigger" telephone number, and a call forwarding number associated with the trigger number. An example of the trigger number might be the subscriber's Internet access telephone number. An example of the call forwarding number might be the subscriber's mobile telephone number.
A determination is made, e.g., a flag is set in the subscriber record, whenever the subscriber is engaged in a communication initiated to the trigger number. Thereafter, incoming calls directed to the subscriber are automatically forwarded to the call forwarding number. However, if the subscriber is currently engaged in a communication with a telephone number other than the trigger number registered in the subscriber's call forwarding service record, incoming calls are handled in a manner other than forwarding the incoming call to the call forwarding number. Such other procedures might include, for example, generation of a busy signal, execution of a call waiting service, or execution of a call completion service.
Conveniently, the subscriber can subscribe to the service, provide the necessary information to implement the service, and activate/deactivate the service via a standard DTMF telephone set. Voice prompts may be employed to prompt the subscriber to enter the necessary information by pressing DTMF buttons on a telephone set. More than one trigger number and corresponding call forwarding number can be recorded in the subscriber's selective call forwarding record. In other words, if the subscriber is currently engaged in a communication involving a second trigger number recorded in the subscriber's record, an incoming call directed to the subscriber is automatically forwarded to the second call forwarding number stored in the subscriber's record as corresponding to the second trigger number. While the first and second call forwarding numbers may be different, e.g., one to the subscriber's mobile telephone number and the other to the subscriber's voice mailbox, they may also be the same, e.g., all selectively forwarded calls are routed to the subscriber's mobile telephone.
The present invention may be implemented in a number of environments including a traditional public switch telephone network (PSTN) as well as in an intelligent network (IN). In a traditional PSTN, the selective call forwarding service may be implemented in a local switching node such as the local exchange connected to the subscriber's communication line. A computer in the local exchange stores the selective call forwarding records for various subscribers in a database and implements the selective call forwarding service following programmed instructions stored in a program memory. A significant advantage of this implementation is that no new hardware is needed at the local exchange since the necessary computer and switching hardware are already in place in modem digital exchanges.
The present invention may also be implemented in an "intelligent" communications network which includes a switching node detecting one or more trigger conditions and a control node cooperatively connected to the switching node making the necessary call control decisions. When the switching node detects that an incoming call is directed to a selective call forwarding subscriber number, the switching node requests call handling instructions from the control node. The control node instructs the switching node to route the incoming call to a first call forwarding number established for the subscriber only if the subscriber is engaged in a communication involving a trigger telephone number associated with the call forwarding number. If the subscriber is not engaged in a communication involving the trigger telephone number, the control node instructs the switching node to take some other action other than routing the incoming call to the corresponding forwarding number. An intelligent network implementation is quite flexible and is easily incorporated with a wide variety of services already provided by existing intelligent networks.
These and other objects and features of the present invention will now be disclosed in further detail in conjunction with the attached drawings and detailed description of the invention set forth below.